We offer a new way to look at the Large Magellanic Cloud through stellar mono-abundance and mono-age-mono-abundance maps. These maps are based on ≳500000 member stars with photo-spectroscopic [M/H] and age estimates from Gaia DR3 data, and they are the first area-complete, metallicity- and age-differentiated stellar maps of any disk galaxy. Azimuthally averaged, these maps reveal a surprisingly simple picture of the Milky Way's largest satellite galaxy. For any [M/H] below -0.1 dex, the LMC's radial profile is well described by a simple exponential, but with a scale length that steadily shrinks towards higher metallicities, from nearly 2.3~kpc at [M/H]=−1.8 to only 0.75~kpc at [M/H]=−0.25. The prominence of the bar decreases dramatically with [M/H], making it barely discernible at [M/H]≲−1.5. Yet, even for metal-rich populations, the bar has little impact on the azimuthally averaged profile of the mono-abundance components. Including ages, we find that the scale length is a greater function of age than of metallicity, with younger populations far more centrally concentrated. At old ages, the scale length decreases with increasing metallicity; at young ages, the scale-length is independent of metallicity. These findings provide quantitative support for a scenario where the LMC built its stellar structure effectively outside in.
@article{arxiv.2403.08516,
title = {What Does the Large Magellanic Cloud Look Like? It Depends on [M/H] and Age},
author = {Neige Frankel and Rene Andrae and Hans-Walter Rix and Joshua Povick and Vedant Chandra},
journal= {arXiv preprint arXiv:2403.08516},
year = {2024}
}
Comments
Submitted to ApJ; constructive comments would be appreciated